888 EXPERIMENT STATION RECORD. 



flowers which tend to foul badly when placed in water some benefit was de- 

 rived by the use of such chemicals as zinc sulphate, copper sulphate, manga- 

 nese sulphate, and admixtures of strontium and barium chlorid with calcium 

 chlorid in killing micro-organisms. The author points out that the possibilities 

 of prolonging the keeping qualities of flowers are much greater with flowers 

 which have a long period of life. The desirability of experiments with flowers 

 of this kind is suggested. 



FORESTEY. 



Studies in tolerance of New England forest trees. — II, Relation of shade 

 to evaporation and transpiration in nursery beds, G. P. Bubns and Fbances 

 P. Hooper (Vermont Sta. Bui. 181 {1914), pp. 235-262, i)ls. 8, figs. 2).— In con- 

 tinuation of previous work with forest seedlings (E. S. R., 31, p. 640) the authors 

 are conducting a study of the effect of shade upon the physical conditions for 

 the germination and development of seedlings. The experiments here re- 

 ported were carried on with white pine seedlings during the summer of 1913. 

 The work deals particularly with the effect of lath screens on evaporation from 

 the seed bed and on transpiration from the seedlings. An attempt was also 

 made to determine the relation between the water loss from the seedlings and 

 evaporation as measured by both black and white porous atmometer cups. 

 Three seed beds were used in the experiment, the conditions being the same for 

 all, except that the first was given no shade on the top ; the second was covered 

 with a lath screen in which the laths were spaced one lath's width apart; and 

 the third was covered with a solid lath screen. All determinations of water 

 losses were made by weight. The plants used for weighing were grown in pots 

 plunged in the seed beds, the tops of the pots being covered with rubber dams 

 to prevent evaporation. The series of observations reported extended over the 

 first two weeks of August. The data are presented in a series of curves and 

 tables and discussed. 



The responses of the atmometers and plants were not identical, the quantita- 

 tive responses differing more than the qualitative responses. In the half shade 

 bed the differences observed in responses of instruments and plants were less 

 than those observed in the no shade bed, the effect of half shade upon the plants 

 being more marljed than on the instruments. Both plants and atmometers lost 

 but little water In the full shade bed. The evaporation-transpiration coefficients 

 based on the unit of dry weight of the plants for no shade, half shade, and full 

 shade beds show that the response of the plant agrees more closely with the 

 black atmometer than with the white atmometer. A comparison of the losses 

 from seedlings from the no shade bed with the losses from 2- and 3-year-old 

 potted plants in the open shows that the seedlings give off water much more 

 rapidly than the older plants, thus indicating the need of some protection for 

 young plants. The daily averages of the losses from instruments and plants 

 were found to smooth out extremes and conceal quantitative differences, thus 

 minimizing the value of conclusions based on general averages. 



The authors conclude that in order to determine a definite relation between 

 atmometer and plant measurements "we need to know the effect of variation 

 in each of the following factors: Light, wind velocity, humidity, and temper- 

 ature on instruments and plants." 



A brief bibliography of consulted literature Is appended. 



Tree growth and seed, J. B. Berry {Jour. Heredity, 5 {1914), No. 10, pp. 

 4S1-4S4, flgs. 2). — ^A brief review of Engler's Investigations relative to the 

 influence of environment on tree growth (K. S. R., 30, p. 239). 



